In order to anchor mounting bolts or the like in a concrete slab or panel, it is desirable to provide bores in the slab with recessed grooves. Similarly, when two neighboring concrete slabs abutting against each other are to be anchored to each other, such recessed grooves are necessary in bores that pass through the interface between the two neighboring slabs. These bores extend preferably in such a way through the interface, that the central bore axis coincides with the plane of the interface and preferably also so that the bore axis extends perpendicularly to the surface of the two neighboring slabs.
For example, neighboring concrete slabs forming a road surface or runway, are to be anchored to each other in such a way that they cannot be displaced in the vertical direction relative to each other.